3rd trimester ultrasound question

Ma

How many ultrasounds will everyone have for the 3rd trimester? I know every OB is different.

I’m 25 weeks and my next appt is 28 weeks. She said I could have my 3rd trimester before then, or wait until 32 weeks for the 4D. I haven’t had one since 17 weeks which was my anatomy scan.

Should I call to see if I can have one sooner, or just wait until 32 weeks??